Electrical apparatus



March 22, 1966 56 6| 5e g ll I A5 \n F1 57. 59 --eo INVENTOR. l9 LLOYD c. JOHNSON 7 =q .Fi q;

L. C. JOHNSON ELECTRICAL APPARATUS Filed Dec. 5, 1960 ATTORN YS 3,242,364 Patented Mar. 22, 1966 3,242,364 ELECTRICAL APPARATUS Lloyd C. Johnson, Sidney, N.Y., assignor to The Bendix Corporation, Sidney, N .Y., a corporation of Delaware Filed Dec. 5, 1960, Ser. No. 73,602 6 Claims. (Cl. 310-263) This invention relates to electrical apparatus, and more particularly relates to apparatus having a shaft and a member having a sleeve-like portion surrounding and fixedly connected to the shaft. The invention also relates to a method of assembling such parts of an apparatus.

The invention has among its objects the provision of an improved, simplified means for connecting a member having a sleeve-like portion to a shaft upon which it is mounted.

A further object of the invention lies in the provision of an improved method of assembling such member upon and connecting it to the shaft.

The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only, and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a view in axial longitudinal section through a combined alternator and distributor having a rotor connected to the shaft in accordance with the invention, certain of the parts being shown in elevation;

FIG. 2 is a schematic view depicting a first step in the assembly of the rotor on the shaft, portions of the schematically shown assembling apparatus being shown in axial section, certain of the other parts being shown in elevation;

FIG. 3 is a view similar to FIG. 2 showing elements of the electrical apparatus being assembled in a later stage of the assembling operation; and

FIG. 4 is a view in longitudinal section of the finally assembled shaft and rotor held in the lower assembling tool, certain of the parts being shown in elevation.

The apparatus and method of the present invention represent improvements upon th-ose disclosed and claimed in the application of Richard B. Clark, Serial No. 814,330, filed May 19, 1959, assigned to the now Patent No. 3,150,278, assignee of the present application. The device shown in FIG. 1 herein is a combined alternator and distributor, as is that of the Clark application. Such alternator and distributor may advantageously be employed in the ignition system of internal combustion engines of the spark ignited type. The present invention relates to an improved means for mounting the magnet-carrying rotor of the alternator upon the shaft thereof, and to the improved method of assembling the rotor upon the shaft.

Turning now to the drawings, the combined alternator and distributor shown in FIG. 1 is generally designated by the reference character 10. Apparatus has a first generally cylindrical hollow housing part 11, preferaby made of metal, and a second generally cylindrical hollow housing part 12 aligned and interfitting with housing part 11, the two housing parts 11 and 12 having journalled therewithin an axially extending main shaft 13. The housing is completed by a cap portion 14, made of electrically insulating material such as a molded plastic, such cap functioning to house and carry parts of the distributor portion of the apparatus.

Shaft 13 has an outer end portion 15 which extends outwardly through the end wall of housing portion 12. Shaft portion 15 is journalled in a ball bearing 16 which is mounted, as shown, in the end wall of the housing part 12. A collar 17 on shaft 13 inwardly of the ball bearing serves to limit axial travel of the shaft in an outward direction. A threaded outer end portion 19 on the shaft permits the shaft to be connected to a driving means such as a gear whereby it is driven in synchronism with the engine.

Fixedly secured to shaft 13 is :a rotor 20 having a first pole piece-carrying member 21, a cylindrical permanent magnet 25 and a second pole piece-carrying member 24. Each of members 21 and 24 is of generally U shape, there being axially directed, diametrically opposed pole pieces on the end flanges thereof. Such pole pieces of member 21 are designated 22. Members 21 :and 24 are directed oppositely and are displaced around the axis of shaft 13 with respect to each other. Opposite ends of permanent magnet 25 are of opposite magnetic polarity, so that successive pole pieces on the rotor are likewise of opposite polarity. Such pole pieces cooperate with pole shoes, of which one is shown at 26, of a laminated magnetic metal core which is secured to the housing and surrounds the rotor.

The apparatus is provided with a number of series connected coils, of which one is shown at 27, which are disposed about each of the poles of the core. The core is held in a housing by the provision of radially projecting ear portions 29 which are received in recesses 30 in housing part 12, as shown. A screw 31 threaded into housing part 12 extends through e'ar portion 29 to hold the core in place. Housing parts 11 and 12 are held together, with the inner end of part 12 in a recess 32 on part 11 by a number of elongated screws 34.

Housing part 11 is provided with a transverse partition 35 intermediate its length, such partition serving to support a bushing 36 which journals the inner end of shaft 13. A cam 37 fixedly secured to the shaft by a pin 39 serves to actuate a breaker assembly 41 which is mounted on partition 35 by a pin 40. A lead wire 42 extends from one end of the series connected coils 27 to a terminal 44 mounted in an insulating bushing 45 affixed to housing part 11.

The inner end of shaft 13 carries a distributor rotor 45 having a body 47 upon which is secured a central contact 49. Contact 49 cooperates with a central fixed contact 50 mounted on cap 14, contact 50 being adapted to be connected to a high tension lead (not shown) by a socket contact 51. The distributor rotor 46 carries a radially directed finger 52 which is adapted sequentially to cooperate with a number of equally spaced contacts 54 affixed to cap 14. A socket 55 is provided on cap 14 for each of contacts 54, whereby the contacts may be connected to the respective spark plugs of the engine.

The rotor 20 is connected to shaft 13 through the medium of novel wedge-type mounting means shown more clearly in FIGS. 2, 3, and 4. As there shown, the shaft 13 is provided with first and second axially Q) spaced knurled portions 56 and 57 which are spaced at approximately the distance between the end flanges on the two U-shaped pole piece-carrying members of the rotor. Disposed about the shaft at such knurled portions 56 and 57 are two oppositely tapered annular wedge members 61 and 65, respectively. Such wedge members, which are preferably made of a metal having a hardness on the same order as those of the shaft 13 and the U-shaped pole piece-carrying members 21 and 24, have a force fitting engagement with the shaft and with frusto-conical seats in the members 21 and 24. The engagement between the parts is such as permanently to hold the rotor parts in engagement with each other and the composite rotor in a fixed position both axially and angularly with respect to the shaft.

The connections between the shaft and the rotor, and the method of forming the combination of shaft and rotor will be more fully understood upon consideration of FIGS. 2, 3, and 4.

The assembling apparatus includes a press such as an arbor press (not shown) having a lower tool or jaw 59 and an upper tool or plunger 64. The tool 59 has a central vertical passage 60 therein of such diameter as snugly and accurately to receive portion 15 of shaft 13 and of such depth that the shaft is supported therein by the collar 17 on the shaft. The shaft is first mounted in tool 59 as shown. Following this, a first wedge member 61 is telescoped over the shaft and slid downwardly so that it rests upon collar 17. Wedge member 61 is disposed so that it tapers in an upward direction. Pole piece-carrying member 21 is then slid downwardly over the shaft, and a first assembling sleeve 62 is telescoped over the upper end of the shaft so that it lies upon the upper surface of the end flange of member 21. Plunger 61 of the press is then lowered forcibly to thrust member 21 downwardly into the position shown in FIG. 3 wherein wedge member 61 has been advanced appreciably into the tapered seat 63. As a result, wedge 61 has been deformed somewhat so that its inner wall interlocks with the serrations on the knurled portion 56 of the shaft and so that members 21, 61, and 13 are firmly secured to each other against relative rotation and any further axial movement.

The magnet 25 and the second pole piece-carrying member 24 are then assembled as shown in FIG. 3. A second wedge member 65, disposed so as to taper downwardly, is then telescoped about the shaft. A second, smaller assembling sleeve 66 is telescoped about the upper end of the shaft and is thrust forcibly downwardly by the plunger 64 of the press. Such second pressing operation thrusts wedge 65 downwardly within the tapered seat 67 of member 24, and deforms such wedge so that it lockingly interfits with the serrations 57 on the shaft. Although the second thrust is exerted upon the shaft and rotor with the latter supported solely by the shaft 13 and wedge 61, little additional axial movement of the rotor takes place during the second pressing operation because of the previous forceful pressing of the parts together at the lower wedge connection.

Simply by way of illustration, and not for purposes of limitation, the following characteristics and dimensions of the parts employed in making satisfactory wedge connections in accordance with the invention are given. The shaft 13 has a diameter approximately .250". Each of the knurls 56 and 57 consisted of parallel grooves spaced 20 teeth to an inch around the surface of the shaft. After being knurled, the shaft 13 was ground at the location of the knurls to restore it to its initial outer diameter. The annular wedges 61 and 65 had initial inner diameters such that they fitted snugly upon the shaft at the location of the knurls. The shaft 13 was made of steel and the parts 21 and 24 were made of nitrided sintered steel. The included angle of the seats 63 and 67 in the central passages in members 21 and 24 was 8. The included angle of the sidewalls of wedges 61 and 65 was likewise 8. Wedges 61 and 65 were made of stainless steel (a stainless steel designated AMS 5640 has proved satisfactory for this purpose).

Although only one embodiment of the invention has been illustrated in the accompanying drawings and described in the foregoing specification, it is to be expressly understood that various changes, such as the relative dimensions of the parts, materials used, and the like, as well as in the suggested manner of use of the apparatus of the invention, may be made without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. Apparatus comprising a metal shaft, an asembly mounted on the shaft, said assembly comprising two separate longitudinally spaced members and an annular element disposed therebetween, the members and the element being separate and being compressively connected only by the shaft, a sleeve-like portion on each of the members surrounding the shaft, the sleeve-like portions each having a tapered annular seat therein confronting the shaft, and a separate annular externally tapered wedge having an uninterrupted cylindrical wall interposed between each of the seats and the shaft and forcibly engaging them, the seats being longitudinally tapered in opposite directions at shallow angles substantially equaling the angle of taper of the respective wedges, each of the wedges engaging the sleeve-like portion and the shaft with a press fit obtained by thrusting the wedge longitudinally relative tothe member and the shaft in the direction of taper of the wedge and seat, the members and the shaft being held against axial and rotational movement relative to each other solely by the said press fits of the wedges between the shaft and the members.

2. A rotor for electrical apparatus comprising a metal shaft, a rotor mounted on the shaft, said rotor comprising two separate longitudinally spaced pole-carrying members and an annular magnet disposed therebetween, the pole-carrying members and the magnet being separate and being compress sively connected only by the shaft, a metal sleeve-like portion on each of the pole-carrying members surrounding the shaft, the sleeve-like portions each having a tapered annular seat therein confronting the shaft, and a separate annular wedge interposed be tween each of the seats and the shaft and forcibly engaging them, the seats being longitudinally tapered in opposite directions at shallow angles substantially equaling the angle of taper of the respective wedges, each of the wedges engaging the sleeve-like portion and the shaft with a press fit obtained by thrusting the wedge longitudinally relative to the member and the shaft in the direction of taper of the wedge and seat.

3. Electrical apparatus as defined in claim 2, wherein the wedges are made of a metal which has a hardness on the same order as those of the shaft and pole-carrying members.

4. Electrical apparatus as defined in claim 2, wherein the engagement between the wedges and the members constitutes the sole means for holding the members and the wedges against rotational movement with respect to each other.

5. Electrical apparatus as defined in claim 2, wherein the portion of the shaft within each of the wedges is roughened, and each of the wedges is deformed so that its inner wall at least partially interfits with the respective roughened surface of the shaft.

6. Electrical apparatus as claimed in claim 5, wherein the roughened portions of the shaft within the wedges are longitudinally knurled, and each of the wedges is de- 2,632,334 3/1953 7 Williams 287-52.06 X formed so that its inner wall at least partially interfits 2,755,112 7/ 1956 K ik 29526 X with the respective knurled surface of the shaft. 2,874,931 2/1959 Brady 285-339 References Cited by the Examiner 5 121 613 7/ I us ra 1a. UNITED STATES PATENTS 913,957 12/1962 Great Britain. 703,680 7/1902 Vaught 28752.07

1,299,934 3/1919 Harnefl: 5-43 ORIS RADER, Prlmary Exammer- 2,366,459 1/ 1945 Rosa. 10 MILTON O. HIRSHFIEL'D, WHITMORE A. WILTZ,

2,585,453 2/1952 Gallagher et al. 285-382.7 Examiners. 

1. APPARATUS COMPRISING A METAL SHAFT, AN ASSEMBLY MOUNTED ON THE SHAFT, SAID ASSEMBLY COMPRISING TWO SEPARATE LONGITUDINALLY SPACED MEMBERS AND AN ANNULAR ELEMENT DISPOSED THEREBETWEEN, THE MEMBERS AND THE ELEMENT BEING SEPARATE AND BEING COMPRESSIVELY CONNECTED ONLY BY THE SHAFT, A SLEEVE-LIKE PORTION ON EACH OF THE MEMBERS SURROUNDING THE SHAFT, THE SLEEVE-LIKE PORTIONS EACH HAVING A TAPERED ANNULAR SEAT THEREIN CONFRONTING THE SHAFT, AND A SEPARATE ANNULAR EXTERNALLY TAPERED WEDGE HAVING AN UNINTERRUPTED CYLINDRICAL WALL INTERPOSED BETWEEN EACH OF THE SEATS AND THE SHAFT AND FORCIBLY ENGAGING THEM, THE SEATS BEING LONGITUDINALLY TAPERED IN OPPOSITE DIRECTIONS AT SHOLLOW ANGLES SUBSTANTIALLY EQUALING THE ANGLE OF TAPER OF THE RESPECTIVE WEDGES, EACH OF THE WEDGES ENGAGING THE SLEEVE-LIKE PORTION AND THE SHAFT WITH A PRESS FIT OBTAINED BY THRUSTING THE WEDGE LONGITUDINALLY RELATIVE TO THE MEMBER AND THE SHAFT IN THE DIRECTION OF TAPER OF THE WEDGE AND SEAT, THE MEMBERS AND THE SHAFT BEING HELD AGAINST AXIAL AND ROTATIONAL MOVEMENT RELATIVE TO EACH OTHER SOLELY BY THE SAID PRESS FITS OF THE WEDGES BETWEEN THE SHAFT AND THE MEMBERS. 